In terms of security, Windows 10 includes Windows Hello, Microsoft Passport and Windows Defender for anti-malware protection, as well as a commitment to deliver free ongoing security updates for the supported lifetime of the device.

Windows Hello3 greets people by name and lets them log in to their PC without a password - providing instant, more secure access to their Windows 10 devices through biometric authentication.

Windows 10 also lets people interact with their device via the traditional mouse and keyboard, or through more natural ways such as voice, pen or gesture.

Continuum enables devices to transform, enabling elegant transitions of a tablet into a PC, and back - and for a Windows phone to become like a PC .

For gamers,Xbox on Windows 10 brings the expansive Xbox Live gaming network to both Windows 10 PCs and tablets. People can communicate with their friends on Windows 10 PCs and Xbox One while playing any PC game, and share content using Game DVR. People can also stream games directly from their Xbox One console to a Windows 10 tablet or PC in their homes. Games developed for DirectX 12 in Windows 10 will see improvements in speed, efficiency and graphics capability.

From today, people can reserve their free upgrade if they choose. More information is available here and at Windows.com.